Seeds that are planted for agricultural and other purposes are often treated prior to planting. The treatments may accomplish various purposes including attacking target bacteria, molds and fungus that can contaminate seeds or that may be present in the soil. Also seed treatment can include insecticides, pesticides and provide deterrence or prevention of insect and other animal pests that would target seeds. Treatments may also provide fertilizer. Direct application of seed treatment allows for a reduction in the amount of treatment composition that would be required by application to soil after planting for many of the beneficial effects. Post-planting application may not penetrate the soil to a level or location where it would be effective, is weather dependent, and may not be as economical as direct seed application.
Preplanting treatment of seeds, however, involves applications of chemicals and other agents that are expensive and may even be toxic to the environment and workers. Various devices for treatment of seeds in batch or continuous treatment mode are known. U.S. Pat. No. 5,891,246 to Lund, the disclosure of which is hereby incorporated by reference, describes a seed coating apparatus for applying a coating fluid whereby seeds are dispersed with a seed dispersing member. U.S. Pat. No. 4,657,773 to Mueller, the disclosure of which is hereby incorporated by reference, describes a process and apparatus for dressing seed in which seed is guided over a dispensing cone through a jet of dressing and onto a rotary table. German patent No. DE 4411058 to Niklas, the disclosure of which is hereby incorporated by reference, describes a device with a mixing bowl connected to a high speed, multi-turn actuator and a mechanism to feed seed into the mixing bowl. The bowl rotates to rotate seed being treated therein. The seed treating formulation is sprayed in the bowl while the seed is being rotated to uniformly coat the seed with the formulation.
Such treatment apparatuses typically apply treatment products to the seeds at a uniform rate to each batch of seeds and cannot adjust application rate as circumstances dictate, such as, for example, upon a slowing of the feed rate to the seed treating equipment. A significant amount of chemical waste can be generated by applying excess treatment products to batches of seeds without precise controls. Because treatment products can be very expensive, e.g., hundreds of dollars per gallon, this can result in a large economic loss. Such chemical waste can also result in an environmental hazard. Accordingly, there is a need for an improved way to control the amount of treatment products applied to the seeds to minimize waste, particularly at the retail seed level.
Certain computerized large scale seed treaters can adjust application rate based on the weight of “flow” of seeds being processed. That is the seed being conveyed to the treatment applicator is weighed and the application rate may be varied based on the flow rate as measured by weight. There is room for improvement of this methodology as such flow weight measurement is taken over a length of the seed flow and thus requires averaging and cannot readily accommodate dramatic seed flow interruptions or variance. Moreover such equipment is expensive and not generally suitable for use at the retail level. Moreover, the weight of the seed can vary with humidity and then more or less than the optimal amount of treatment fluid may be applied to the seed.
The amount of seed treatment provided to seeds is conventionally determined by the weight of seeds, for example, x volume of treatment fluid for y weight of seeds. A useful measurement to determine the amount of treatment products needed, as well as controlling the rate of coating, is the total surface area of the seeds. The weight of seeds can vary with humidity and other factors whereas the volume of seed correlates more directly with the surface area of the seed.
For certain treatments, including formulations several of treatments applied simultaneously to the seeds, the seeds need to be planted very soon, within hours after application, for optimal effectiveness. Such seed treatment needs to be done at a local level by the seed retailer. This is problematic with existing seed treaters with automatically adjusted treating controls as such are expensive and typically are not easily used for repeated and rapid processing small batches for individual users.